All year long, we write about founders, CEOs, and rock-star engineers. But it takes all kinds of people to make the magic that powers the tech we all use. It's time we tell their stories.

We asked our contacts—some of those much-sung power brokers and other insiders—to nominate people whose drive, passion for work, and accomplishments, not their rank or title, made a difference this year. We looked for people at companies small and large throughout the tech sector.

We think most of the people on this list will feel they shouldn't be on it. Supportive bosses and helpful colleagues, they'll say, ought to get the recognition instead. But their coworkers nominated them for just that reason—these unsung heroes are the least likely to grab the credit they deserve.

Mark Zuckerberg talks a lot about how his social network enables people to have an authentic identity. Sperling helps make that a reality for Facebook's own employees, leading the company's diversity and inclusion efforts.

Thanks to her, 450 employees took part in this year's San Francisco Gay Pride Parade—up 50% from last year—and Facebook's new campus includes unisex bathrooms to help transgender employees feel comfortable. GLAAD, a media-watchdog group, gave the company an award this year for its diversity efforts, making it the first social network ever to get such an honor.

A Linux generalist at the security-products company, Black works on behind-the-scenes infrastructure tools, like an automated ordering system that speeds new equipment to data centers. One colleague, Michael Kjellman, wrote in a LinkedIn endorsement, "I'll make this brief: When I get stuck on something, I go to BJ ... as does the entire company."

From that, Black may seem like a whiz kid, but by his own admission, he struggled in academia. It ended up taking him 16 years of on-and-off education, at three different schools, to get his bachelor's. But at San Jose State University, where he earned his degree in 2008, the computer-science department named him "Outstanding Graduating Senior of the Year."

Shiva Rajaraman, for making YouTube ubiquitous

The buzz is on Google+, but YouTube is the search giant's real social network. Rajaraman's big push this year has been to roll out a new, consistent look wherever videos play—on iPhones and iPads, Android devices, Xbox and Wii game consoles, and more.

That means YouTube, already ubiquitous on the Web, is now on 400 million devices. Rajaraman deserves a lot of the credit for that feat.